1. Field of the Invention
The present invention relates to an interface and a method allowing a user to intuitively explore and navigate within a collection of data. The invention is particularly suited for use with computer programs.
2. Description of Related Art
Over the last decades, the way information is stored and managed has dramatically changed. For centuries, information was stored in physical libraries. Librarians administered the inventory, and only few people had access. Nowadays, the increasing use of electronic storage systems makes it easy and cheap to store all kind of information. Huge databases hold millions of documents. Depending on the operating efficiency of the database server, any desired document can be made available within fractions of a second. Furthermore, the computer systems connected to the Internet provide a steadily growing number of documents. A new problem has arisen, and that is finding the desired information.
On computers, documents are typically stored in a file system. A file system can be organized in folders, each folder having further subfolders, if desired. Such a hierarchical organization can be visualized using tools like for instance the WINDOWS® Explorer (produced and distributed as part of the operating system WINDOWS by Microsoft Corp., Seattle, Wash., USA). This software has a graphical user interface (GUI) that is often referred to as a tree structure, allowing the user to expand or collapse branches and sub-branches, the branches reflecting the folder structure. Although the folder and sub-folder structure allows storing documents in a structured manner, it is often difficult to decide which would be the appropriate location for a document. As a consequence, a lot of time is often spent searching for documents stored on a hard disk of a computer.
Database systems often allow to tack additional information to the documents, like search terms. Also, assigning documents to predefined classes is common. However, there is always a compromise to be made. Limiting the number of classifications or search terms helps to maintain a certain degree of lucidity, but restricts the user in adding references. Providing greater freedom in entering search terms and classifications quickly ends up in a counterproductive tangle.
In the Internet, so called hyperlinks are widely used. A hyperlink contains the address of another document. If the user “follows” the hyperlink, the document located at the respective address can be accessed, However, it can still be a tedious exercise to find what one is searching for. One major reason is that the hyperlinks are not managed. A link may point from one document to any given other document, but at the target document, there is no information available about all the links that are pointing to this document. Especially, when the document is close to what the user is actually looking for, it would be desirable to know about all the hyperlinks pointing to that document and follow them “backwards” in order to find a document that either contains the desired information or has hyperlinks pointing to other matching documents.
But there is no such possibility. The only option to walk the way backwards that led to such a document is by using the capability of most Internet browsers of storing the addresses of the documents accessed within one session. So the “Back” button of the Internet browser can guide the user back to the document from where the link pointed to the recent document, not because such information is stored in the documents, but only because the browser remembers previous addresses.
Documents in a database are often administered in a hierarchical manner. Such hierarchical structures are typically visualized by using a tree structure. Such a tree structure shows a number of items, and each item may have an arbitrary number of sub-items. Several interrelated items will typically be grouped under a superordinate item. While the tree structure appropriately depicts the hierarchy of items, such a structure has other limitations: Each item has only one “parent” item, in other words only one link is pointing to each item. Due to this, only one path leads to a document. If the creator of the structure had a different understanding of a logical configuration than any given user, then that user may never find a desired piece of information.
A requirement managing tool named DOORS® (produced and distributed by Telelogic AB, Malmo, Sweden) allows organizing documents in a hierarchical manner. The hierarchy is visualized in a tree structure (similar to the WINDOWS Explorer). Additionally, links can be generated pointing from an item to any other item. However, the link structure cannot be viewed in a lucid manner, and navigating along the links is a tedious exercise. Only one level of links can be viewed at a time. In other words, for each item only the links pointing directly to the item and pointing away from the item are displayed. Especially, when links have led to a fruitless location, reverting to a more promising junction is not supported. This type of navigation is very similar to exploring the content of a computer hard disk by using old DOS versions, where on each directory level, the DIR command would list the subdirectories, and one had to change to one of the subdirectories to be able to find out more about further subdirectories by again using the DIR command. This mode of navigation significantly lacks the efficiency and convenience provided for instance by a tree view display.
Relational databases allow creating a complex data structure, where tables or certain kind of data entries are referring to other tables or data entries in order to project a complex structure into a database. But such structure is predefined to contain information in a certain structure. The links are part of a predefined structure, not part of the information itself. Therefore it requires the skill-set of a database architect to build and maintain such complex database systems.
The exploding amount of information related to a certain subject tends to dilute the understanding of such subject. Even more, for a comprehensive understanding of a subject it is required to communicate the inherent structure between information items. It is not sufficient to list or summarize the information items itself. But such an inherent structure is often too complex to simply being projected to either one hierarchical tree or an anarchistic deployment of unilateral links. The thesis can be made that in a complex structure, a significant part of the information itself is contained in the structure or network of the information items.
A typical prior art visualization mode of items being interrelated by pointers is shown in FIG. 26. Although only 12 items are present and the number of pointers is only 16, the representation of the network is already confusing. If a data collection having thousands of items is presented to the user in this manner, it is a hard task to locate an item holding the information the user is looking for.
Accordingly, a need remains for an interface and a method allowing a user to intuitively explore a complex collection of data, and to navigate within the collection using references pointing from data items to other data items.